The kernel uses open code to check if a process is in root PID namespace or not in several places.
Suggested by Suzuki, this patch set is to create a helper function task_is_in_root_ns() so we can use it replace open code.
To test this patch set, I built Arm64 kernel with enabling all relevant modules, and verified the kernel with CoreSight module on Arm64 Juno board.
Leo Yan (7): pid: Introduce helper task_is_in_root_ns() coresight: etm3x: Use task_is_in_root_ns() to check PID namespace coresight: etm4x: Use task_is_in_root_ns() to check PID namespace connector/cn_proc: Use task_is_in_root_ns() to check PID namespace coda: Use task_is_in_root_ns() audit: Use task_is_in_root_ns() taskstats: Use task_is_in_root_ns()
drivers/connector/cn_proc.c | 2 +- drivers/hwtracing/coresight/coresight-etm3x-sysfs.c | 8 ++++---- drivers/hwtracing/coresight/coresight-etm4x-sysfs.c | 8 ++++---- fs/coda/inode.c | 2 +- fs/coda/psdev.c | 2 +- include/linux/pid_namespace.h | 5 +++++ kernel/audit.c | 2 +- kernel/taskstats.c | 2 +- 8 files changed, 18 insertions(+), 13 deletions(-)
Currently the kernel uses open code in multiple places to check if a task is in the root PID namespace with the kind of format:
if (task_active_pid_ns(current) == &init_pid_ns) do_something();
This patch creates a new helper function, task_is_in_root_ns(), it returns true if a passed task is in the root PID namespace, otherwise returns false. So it will be used to replace open codes.
Suggested-by: Suzuki K Poulose suzuki.poulose@arm.com Signed-off-by: Leo Yan leo.yan@linaro.org --- include/linux/pid_namespace.h | 5 +++++ 1 file changed, 5 insertions(+)
diff --git a/include/linux/pid_namespace.h b/include/linux/pid_namespace.h index 7c7e627503d2..bf82b373f022 100644 --- a/include/linux/pid_namespace.h +++ b/include/linux/pid_namespace.h @@ -86,4 +86,9 @@ extern struct pid_namespace *task_active_pid_ns(struct task_struct *tsk); void pidhash_init(void); void pid_idr_init(void);
+static inline bool task_is_in_root_ns(struct task_struct *tsk) +{ + return task_active_pid_ns(tsk) == &init_pid_ns; +} + #endif /* _LINUX_PID_NS_H */
This patch uses helper task_is_in_root_ns() to replace open code for checking if a task is in root PID namespace.
Signed-off-by: Leo Yan leo.yan@linaro.org --- drivers/hwtracing/coresight/coresight-etm3x-sysfs.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-etm3x-sysfs.c b/drivers/hwtracing/coresight/coresight-etm3x-sysfs.c index e8c7649f123e..baba16ad9bb1 100644 --- a/drivers/hwtracing/coresight/coresight-etm3x-sysfs.c +++ b/drivers/hwtracing/coresight/coresight-etm3x-sysfs.c @@ -1030,7 +1030,7 @@ static ssize_t ctxid_pid_show(struct device *dev, * Don't use contextID tracing if coming from a PID namespace. See * comment in ctxid_pid_store(). */ - if (task_active_pid_ns(current) != &init_pid_ns) + if (!task_is_in_root_ns(current)) return -EINVAL;
spin_lock(&drvdata->spinlock); @@ -1058,7 +1058,7 @@ static ssize_t ctxid_pid_store(struct device *dev, * As such refuse to use the feature if @current is not in the initial * PID namespace. */ - if (task_active_pid_ns(current) != &init_pid_ns) + if (!task_is_in_root_ns(current)) return -EINVAL;
ret = kstrtoul(buf, 16, &pid); @@ -1084,7 +1084,7 @@ static ssize_t ctxid_mask_show(struct device *dev, * Don't use contextID tracing if coming from a PID namespace. See * comment in ctxid_pid_store(). */ - if (task_active_pid_ns(current) != &init_pid_ns) + if (!task_is_in_root_ns(current)) return -EINVAL;
val = config->ctxid_mask; @@ -1104,7 +1104,7 @@ static ssize_t ctxid_mask_store(struct device *dev, * Don't use contextID tracing if coming from a PID namespace. See * comment in ctxid_pid_store(). */ - if (task_active_pid_ns(current) != &init_pid_ns) + if (!task_is_in_root_ns(current)) return -EINVAL;
ret = kstrtoul(buf, 16, &val);
To avoid open code, this patch uses the helper task_is_in_root_ns() to check if a task is in root PID namespace.
Signed-off-by: Leo Yan leo.yan@linaro.org --- drivers/hwtracing/coresight/coresight-etm4x-sysfs.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c index a0640fa5c55b..cd87ad8456d7 100644 --- a/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c +++ b/drivers/hwtracing/coresight/coresight-etm4x-sysfs.c @@ -1890,7 +1890,7 @@ static ssize_t ctxid_pid_show(struct device *dev, * Don't use contextID tracing if coming from a PID namespace. See * comment in ctxid_pid_store(). */ - if (task_active_pid_ns(current) != &init_pid_ns) + if (!task_is_in_root_ns(current)) return -EINVAL;
spin_lock(&drvdata->spinlock); @@ -1918,7 +1918,7 @@ static ssize_t ctxid_pid_store(struct device *dev, * As such refuse to use the feature if @current is not in the initial * PID namespace. */ - if (task_active_pid_ns(current) != &init_pid_ns) + if (!task_is_in_root_ns(current)) return -EINVAL;
/* @@ -1951,7 +1951,7 @@ static ssize_t ctxid_masks_show(struct device *dev, * Don't use contextID tracing if coming from a PID namespace. See * comment in ctxid_pid_store(). */ - if (task_active_pid_ns(current) != &init_pid_ns) + if (!task_is_in_root_ns(current)) return -EINVAL;
spin_lock(&drvdata->spinlock); @@ -1975,7 +1975,7 @@ static ssize_t ctxid_masks_store(struct device *dev, * Don't use contextID tracing if coming from a PID namespace. See * comment in ctxid_pid_store(). */ - if (task_active_pid_ns(current) != &init_pid_ns) + if (!task_is_in_root_ns(current)) return -EINVAL;
/*
To avoid open code, this patch uses the helper task_is_in_root_ns() to check if task is in root PID namespace.
Signed-off-by: Leo Yan leo.yan@linaro.org --- drivers/connector/cn_proc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/connector/cn_proc.c b/drivers/connector/cn_proc.c index 646ad385e490..b8a4fa366b28 100644 --- a/drivers/connector/cn_proc.c +++ b/drivers/connector/cn_proc.c @@ -358,7 +358,7 @@ static void cn_proc_mcast_ctl(struct cn_msg *msg, * other namespaces. */ if ((current_user_ns() != &init_user_ns) || - (task_active_pid_ns(current) != &init_pid_ns)) + !task_is_in_root_ns(current)) return;
/* Can only change if privileged. */
Replace open coded checking root PID namespace with task_is_in_root_ns().
Signed-off-by: Leo Yan leo.yan@linaro.org --- fs/coda/inode.c | 2 +- fs/coda/psdev.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/fs/coda/inode.c b/fs/coda/inode.c index d9f1bd7153df..a7d630ac522e 100644 --- a/fs/coda/inode.c +++ b/fs/coda/inode.c @@ -152,7 +152,7 @@ static int coda_fill_super(struct super_block *sb, void *data, int silent) int error; int idx;
- if (task_active_pid_ns(current) != &init_pid_ns) + if (!task_is_in_root_ns(current)) return -EINVAL;
idx = get_device_index((struct coda_mount_data *) data); diff --git a/fs/coda/psdev.c b/fs/coda/psdev.c index b39580ad4ce5..54db13bf2e06 100644 --- a/fs/coda/psdev.c +++ b/fs/coda/psdev.c @@ -270,7 +270,7 @@ static int coda_psdev_open(struct inode * inode, struct file * file) struct venus_comm *vcp; int idx, err;
- if (task_active_pid_ns(current) != &init_pid_ns) + if (!task_is_in_root_ns(current)) return -EINVAL;
if (current_user_ns() != &init_user_ns)
Replace open coded checking root PID namespace with task_is_in_root_ns().
Signed-off-by: Leo Yan leo.yan@linaro.org --- kernel/audit.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/audit.c b/kernel/audit.c index 121d37e700a6..c71d4182c05d 100644 --- a/kernel/audit.c +++ b/kernel/audit.c @@ -1034,7 +1034,7 @@ static int audit_netlink_ok(struct sk_buff *skb, u16 msg_type) case AUDIT_MAKE_EQUIV: /* Only support auditd and auditctl in initial pid namespace * for now. */ - if (task_active_pid_ns(current) != &init_pid_ns) + if (!task_is_in_root_ns(current)) return -EPERM;
if (!netlink_capable(skb, CAP_AUDIT_CONTROL))
Replace open coded checking root PID namespace with task_is_in_root_ns().
Signed-off-by: Leo Yan leo.yan@linaro.org --- kernel/taskstats.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/taskstats.c b/kernel/taskstats.c index 2b4898b4752e..c6a19d3911b3 100644 --- a/kernel/taskstats.c +++ b/kernel/taskstats.c @@ -284,7 +284,7 @@ static int add_del_listener(pid_t pid, const struct cpumask *mask, int isadd) if (current_user_ns() != &init_user_ns) return -EINVAL;
- if (task_active_pid_ns(current) != &init_pid_ns) + if (!task_is_in_root_ns(current)) return -EINVAL;
if (isadd == REGISTER) {
-
Leo Yan